Associate
You need to take a step back from all this, it's not you're problem
I'd personally say to them you've done you're best but they need to speak to a professional.
You're creating yourself stress and worry, you're going to end up ordering parts that you're not sure will fix it.
The bit of money you'd have got wouldn't make up for all the grief this is causing you. You tried to help them with a cheap fix but unfortunately they need to seek expert advice.
Job done, mo more worries.